Disintegrating bullet for practice cartridges for small-arms or automatic weapons



Aprll 6 R. GERMERSHAUSEN 3, ,7

DISINTEGRATING BULLET FOR PRACTICE CARTRIDGES FOR SMALL-ARMS OR AUTOMATIC WEAPONS Filed Dec. 27, 1966 IN V EN TOR.

Fla Hum) cclenensuaus e TTOIZ-Nb YS United States Patent Ofiice 3,435,769 Patented Apr. 1, 1969 3 435,769 DISINTEGRATING BULLET FOR PRACTICE CARTRIDGES FOR SMALL-ARMS R AUTO- MATIC WEAPONS Raimund Germershausen, Dusseldorf-Nerd, Germany, as-

signor to Rheinmetall G.m.b.H., Dusseldorf, Germany, a company of Germany Filed Dec. 27, 1966, Ser. No. 604,697 Claims priority, application Germany, Jan. 7, 1966,

Int. or. F42b 11/36 US. Cl. 102 92.7 12 Claims ABSTRACT OF THE DISCLOSURE Background of the invention Disintegrating bullets are known that consist substantially of a plastic casing which is filled with heavy pulverous material and is sealed by means of a base which also consists of plastic.

It is desired that such a bullet is substantially the same as a live bullet as regards its outer shape and its weight. Only if this requirement is met is it possible for the bullet to be used in automatic Weapons as Well without a detrimental elfect on the breech and loading mechanism of the gun. The weight and shape of the bullet must allow the buildup of a predetermined gas pressure in the powder chamber, for on this depends the operation of the entire gun mechanism; it is, however, equally important that the bullet disintegrates readily immediately after leaving the barrel so that it cannot do any damage beyond a predetermined distance from the barrel muzzle. For this purpose, the known bullet casings are provided in the longitudinal direction with several intended break lines.

However, due to the use of resilient plastic casings with longitudinal weakening lines, all known disintegrating bullets have the common disadvantage of not being radially stable enough to ensure optimum resistance to withdrawal or separation from the cartridge casing mouth, i.e., the front end of the cartridge case of the bullet, and to ensure a good seal between the bullet and the inside wall of the barrel in the region of the guide ridge and a good centring of the bullet in the barrel.

'A further disadvantage of these known disintegrating bullets is that they do not take s-ufiicient account of the stresses between casing and base on firing when choosing the material thicknesses, with the result that the bullet base often breaks off and the casing leaves the base behind, which results in pulverous filling material being thrown against the inside wall of the barrel. This results in a high barrel wear.

Summary of the invention It is an Object of the present invention to provide a disintegrating bullet for practice cartridges for smallarms or automatic weapons, which both withstands in improved manner the extremely high mechanical stresses during the feed and loading operations and also ensures a trouble-free operation of the gun mechanism with low barrel wear. It is a further object of this invention to provide a bullet which has the feature of disintegrating readily after leaving the barrel.

In realizing these objects of this invention a hollow shank adjoining the bullet base is provided projecting into the casing into the region of a widened guide ridge, said shank being provided with a surface of contact which bears against the inside wall of the bullet casing and which extends preferably over the entire length of the shank. This gives in the highly stressed rear portion of the bullet, i.e., from the base to the guide ridge, a continuous longitudinal and transverse strengthening of the bullet which ensures that the bullet base remains intact on firing and that there is an optimum resistance to separation of the bullet casing and the cartridge case;

finally, a good seal of the bullet with respect to the barrel in the region of the guide ridge is ensured. A further feature of this invention consists in that the end face of the hollow shank is employed as support for a reinforcement plate arranged in the bullet casing in the region of the guide ridge. This secures the reinforcement plate against displacement within the bullet casing. If it were not so supported, the reinforcement plate would be able to move somewhat rearwardly on firing in spite of the bullet filling and would thus no longer provide support for the guide ridge. The result would be an insufiicient seal between the bullet and barrel, which in extreme cases would make the recoil impulse too weak to ensure satisfactory operation of the gun mechanism.

Brief description of the drawing Some of the objects and advantages of this invention having been stated, others will appear as the description proceeds when taken in connection with the accompanying drawing showing a disintegrating bullet in longitudinal section.

Detailed description of the drawing The bullet or projectile illustrated in the drawing consists substantially of a thin-walled casing 1 extending to the base and a thick-walled base 5. The rear portion of the bullet casing 1 comprises externally an annular thickening which is in the form of a guide ridge or band 2 and the purpose of which is to provide a good seal between the bullet and the barrel and a better centring of the bullet in the barrel. The guide ridge 2 substantially corresponds in thickness to the guide ring of a live bullet, but the width thereof is substantially greater in the case of a disintegrating bullet. When supported by a reinforcing member which is arranged inside the bullet and which can consist of a reinforcement plate '8 offering suitable resistance to the external concentric pressure, such a wide guide ridge 2 ensures an effective sealing and centring of the bullet in the barrel. The portion of the bullet casing 1 which extends below the guide ridge 2 to the base comprises a transverse grooving 3 which, alone or in conjunction with an adhesive, ensures a firm fitting in the mouth of the cartridge case. The inner surface of the mouth of the cartridge case may of course also be provided with a corresponding transverse grooving, but the advantage of a smooth cartridge mouth is that the cartridge case can be used if desired for live ammunition as well. Finally, the bullet casing 1 is provided on the inside with a plurality of intended break lines 4 which extend as weakening grooves in the longitudinal direction of the bullet from the tip down to the guide ridge 2.

The thick-walled bullet base 5 comprises a long hollow shank 6 whose wall thickness decreases gradually from the base upwardly, the outer surface of said shank extending parallel to the bullet axis. When the bullet base 5 is inserted into the casing 1, the end face of the hollow shank 6 extends up to the guide ridge 2 and serves as axial support for the reinforcing plate 8, which consists of plastic or board. The outer surface of the hollow shank 6 is at the same time the surface of contact with the bullet casing 1. The base comprises a shoulder 7, against which bears the lower end of the casing 1. The width of the shoulder 7 corresponds to the wall thickness of the casing 1.

To ensure satisfactory disintegration of the hollow shank 6 as well, the latter may also be provided with a plurality of intended break lines 9 extending longitudinally.

After insertion of the bullet filling, which may consist of compressed mouldings or briquets 10 and 11 of heavy pulverous filler material, the reinforcing plate 8 is inserted. The base 5, whose hollow shank 6 is also filled with a compressed moulding 12, is then pressed into the open end of the bullet casing 1 until the end face of the shank 6 abuts against the reinforcing plate 8 and the shoulder 7 against the lower edge of the casing 1. The casing 1 and the base 5 are joined together at the shoulder 7 by welding. This may be done thermally or by induction by means of an inlaid metal wire or metal foil, by ul trasonic Welding, or by friction welding.

The welding may be carried out by means of a suitably heated mould in such a manner that the base 5 tapers conically towards the rear.

The advantages of this disintegrating bullet of simple construction are the excellent longitudinal and radial stability, the good seal between the bullet and the inside of the barrel and the good centring of the bullet in the barrel. Thus, on firing the wide guide ridge 2 prevents firing gases flowing past the bullet. With the increasing acceleration of the bullet, the hollow shank 6 is expanded under the effect of the momentum of the filling and pressed firmly agains the inside of the barrel. This provides an excellent gaseealing effect and a good centring of the bullet in the barrel.

When the bullet has left the barrel, the hollow shank 6 subjected to the internal stress due to the filling disintegrates along the break lines 9, the bullet casing 1 beginning to split at the same time. The strips formed on disintegration of the hollow shank 6 and reversing towards the outside considerably increase the air resistance, and'as a result the base piece and the casing soon fall to the ground. If the base piece consisting of the hollow shank 6 and the base 5 is made of a particularly brittle plastic, it may be ensured that not only the hollow shank 6 disintegrates into strips, but that the thickwalled base 5 also disintegrates into fragments of small range.

A decisive factor in ensuring that the disintegrating bullet remains intact in the barrel is sufiicient thickness of the bullet base, so that the latter is able to withstand the shearing forces arising on firing due to the various radial stresses between the casing and base. This may, however, also be achieved by using a particularly suitable plastic of high notch impact strength.

In the drawing and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

What is claimed is:

1. A practice projectile having a forward end, a rear end and an axis aligned with the direction of intended flight, comprising a generally tubular projectile casing having a closed forward end, a rear end, an inside surface, an outside surface, and an annular guiding and sealing band projecting radially outward from its outside surface; a separate annular reinforcing member within said projectile casing engaging the inside surface of said projectile casing radially opposite from said band; a base member generally closing the rear end of said projectile casing and extending forwardly to supportingly abut the rear end of said reinforcing member; a readily destructible filler material within said projectile casing; and means for rupturing said projectile casing to release said filler material during firing of the projectile.

2. The practice projectile according to claim 1, wherein said rupturing means is a plurality of generally axially extending grooves in said projectile casing to tear axially.

3. The practice projectile according to claim 1, wherein said filler material is pulverant.

4. The practice projectile according to claim 1, wherein said projectile casing is of one-piece synthetic material construction and said base is of one-piece construction.

5. The practice projectile according to claim 1, wherein said base includes a tubular hollow shank having an outside annular surface engaging the adjacent inside surface of said projectile casing and a forwardly facing annular surface abutting said reinforcing member.

6. The practice projectile according to claim 5, wherein said shank engages said projectile casing over its entire axial length.

7. The practice projectile according to claim 5, wherein said rupturing means is a plurality of generally axially extending grooves in said projectile casing to tear axially; said filler material is pulverant; said projectile casing is of one-piece synthetic material construction and said base is of one piece construction.

-8. The practice projectile according to claim 7, wherein said shank has a radial wall thickness that gradually decreases toward the forward end of the projectile, and said shank outside annular surface being parallel with said axis.

9. The practice projectile according to claim 8, wherein said shank has a forwardly facing annular shoulder surface abutting with and of a radial thickness equal to the rear end of said projectile casing.

10. The practice projectile according to wherein said base and said projectile casing together at said shoulder.

11. The practice projectile according to claim 7, wherein said projectile casing outside surface has a plurality of transverse grooves adjacent the rear end.

12. The practice projectile according to claim 7, wherein said filler material completely fills the inside of said shank rearward of said reinforcing member and completely fills the inside of said projectile casing forward of said reinforcing member.

claim 9, are fused References Cited UNITED STATES PATENTS 3,170,405 2/1965 Jungerman et al. 10241 X 3,242,865 3/1966 Jungerman et al. 10291 3,289,585 12/1966 Rudolph et al. 102-41 FOREIGN PATENTS 1,438,928 4/ 1966 France.

ROBERT F. STAHL, Primary Examiner. 

